Exported planar arcs appear open in autocad

Rhino Rhino for Windows
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When exporting arcs to dxf from Rhino sometimes the lines are open in autocad. Now granted these openings are <.00001 inch in distance, and the vertexes are in the same location. Autocad will join them as a closed curve, but when you are zoomed in they appear open. This might be a visual problem and the problem is somewhere else, however, the machine that this is going to produces erroneous cuts at these points.

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OpenArc_00.0.png752×536 6.8 KB

one thing that seems to fix this is to export using the ‘SaveSmall’ setting on.
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The machine does not produce errors with this setting on. It’s possible the actual fix is from another source but I wanted to see if there are any known issues with exporting open lines and the ‘SaveSmall’ option.

Thanks

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Can you post a Rhino file (before export) with your export settings?

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Yes, Thanks for taking a look.

NoSpline - Export.ini (952 Bytes)
OpenLinesFile.3dm (278.4 KB)

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Dunno, I tried just the two arcs that meet at their end points inside your red circle. Before exporting, I checked the coordinates of each endpoint at max display precision:

I got:
66.1985734,19.5582918,0.0000000
66.1985734,19.5582918,0.0000000

I then imported your .ini file and exported the two arcs as .dxf with your settings. Then I re-imported the .dxf.

I got:
66.1985734,19.5582918,0.0000000
66.1985734,19.5582918,0.0000000

i.e. exactly the same… and to seven decimal places…